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By David P. Lindroth

The Bureau of Mines has developed and successfully tested a hangup clearance module for use in clearing hangups in underground mine chutes and ore passes. The Bureau's tests showed that the hangup clearance module can be effectively used to clear mine hangups. Furthermore, it is believed that clearance using this module is quicker, safer, and more efficient than the method currently used. The hangup clearance module uses a ballistic disk explosive charge that can clear hangups located as far as 50 feet (15.2 m) from the position where the charge is detonated. Mine personnel can therefore set up the module and the charge it contains without being exposed to dangerous areas. This report describes the principles of operation of the module, provides data and drawings for its construction, and gives instructions for its setup and use. The report also summarizes the development of the module, briefly discusses preliminary and underground tests, and lists the current and potential applications of the hangup clearance module to underground mining.

Jan 1, 1982

By Thomas M. Hanna, John W. Anthony, Lee C. Atkinson

Ground water can pose major engineering and environmental problems to the new generation of large, deep gold mines currently being developed throughout the world. It is important that the potential magnitude of these problems be assessed early in the planning of such projects and that any necessary dewatering and environmental remediation programs be designed at least preliminarily in the feasibility stage. The assessment should begin with acquisition of hydrogeologic data during exploration drilling and be followed by carefully designed and analyzed aquifer tests. Once a sufficiently detailed conceptual hydrogeologic model has been defined, state-of-the-art numerical models should be used to estimate ground-water inflows to proposed pits and underground openings, to design and evaluate the potential effects of various dewatering schemes, to define specific environmental impacts, and to predict pore pressures in highwalls relative to slope stability. The modeling results will indicate which method(s) of dewatering will be most effective both technically and economically. If wells are used, it is imperative that they be as hydraulically efficient as possible. There are new methods of drilling and completing dewatering wells that can help assure maximum efficiency.

Jan 1, 1989

By M. Karmis

The development of engineering rock classification systems has received considerable at tent ion during the past few years. The purpose, application and method of assigning an index of rock quality, vary considerably between these systems. Several of them are directed toward the assessment of stability and support potential of an excavation whereas other systems are estimating a particular response of the rock, i.e. blastability or ripability. In the most widely accepted engineering rock classification systems, rock quality is expressed either in terms of meaningful descriptions or by a quantitative evaluation of a geomechanical property or properties. The application of sonic wave parameters in the engineering classification of rock mass and rock material has been the subject of considerable interest amongst investigators. The advantages of utilizing such techniques include minimal sample preparation, capabilities for large scale testing and the ability to perform non- destructive as well as reproducible tests. The purpose of the research presented in this paper was to determine the most appropriate sonic wave parameters for engineering rock classification purposes, to utilize these findings in developing new or modifying existing classification systems and, finally, to apply this information in the prediction and analysis of blasting wave characteristics.

Jan 1, 1984

By T. Imgrund, A. Bischoff, S. Spürk

"Specific conditions of underground coal mines at great depth, such as high temperatures, high rates of methane inflow and natural ventilation pressure provide considerable challenges for the reliable design of appropriate mine ventilation systems. For decades coal mining in Germany has coped with these extreme circumstances. Based on these experiences appropriate software tools for simulating mine ventilation networks have been developed and continuously enhanced. This paper examines differences in the simulation results and underlying calculation methods of two software solutions. The analysis is based on the comparison of FlowNetTM and VentSim DesignTM (Version 5.1) regarding the accurate prediction of fluid mechanical quantities and their validation with real measurements. A special focus lies on exceptional ventilation scenarios typical for deep coal mines, like gas inflows, fire events and buoyancy effects. The purpose of the comparison is the future utilization of the experiences gained during mining at up to 1,500 m depth for state of the art ventilation design. INTRODUCTION Ventilation is an essential component of mine operations—as providing fresh air to workplaces, diluting and removing explosive, toxic or asphyxiating pollutants and assuring sufficient climate conditions. On the other hand, the costs of ventilation contribute to a large extend to the overall operating costs of a mine, as the share in the energy consumption of a mine may be in the range of 25–50% (Belle, 2008). Accordingly, proper design of ventilation systems has been a task since early times. Consequently software for modelling of ventilation networks has been developed in order to improve efficiency and accuracy of calculations (Maleki, 2018). Compressible flow has not been considered by initial ventilation modelling software tools. In Germany, the consideration of changes in airflow density—depending on pressure and temperature—in the algorithms of ventilation simulation software has been started in 1974 by Duepre & Hofbauer. This development had been continued by the Pruefstelle fuer Grubenbewetterung (Test Centre for Mine Ventilation) and resulted in the release of a computer ventilation software named “Wetter”. The mine inspectorate of the German state of North Rhine-Westphalia, which supervises the major coal mining district in Germany, declared ventilation simulation based on compressible flow being “state of the art” in 1985 (Pollak, 1985). This pronouncement made allowance for assessing the consequences of underground fires and downtimes of main fans based on advanced software solutions."

Jan 1, 2019

By G. S. Hume

IN THE autumn of 1922, British Petroleums Ltd. found oil of 14° Baume in a sand 17 ft. thick in its No. 2 well at Wainwright, 120 miles southeast of Edmonton. This greatly encouraged drilling in the Wainwright-Irma area and this past summer several wells were started, three of which are now completed' and the others still being drilled. Of the three completed, No. 4 British Petroleums contains oil; No. 3 British Petroleums gave a show of oil but so far has not given much hope of becoming a commercial producer; and No. 1 Maple Leaf Co., as now finished, is a gas well with a daily flow of gas of about 2,500,000 cu. ft. at a closed pressure of 700 lb. An oil sand is reported . to have been encountered below the producing gas horizon, in the Maple Leaf well but has not been tested. Operations on this well have been suspended for the winter. The Geological Survey of Canada this past summer undertook a geological investigation of this area with the object of defining the structures with which the oil and gas are associated. The 'structure underlying this portion of the plains was supposed to-be a terrace with the western edge dipping into the Alberta syncline and with a monoclinal structure to the east. By accurate leveling on known geological horizons on this terrace, a number of gentle folds were located and it is in these folds that the oil land gas are found. At the British Petroleums Nos. 2-and- 4 oil wells, the western flank of the fold has a gentle dip of only a few feet to the mile to the southwest whereas the strata on the eastern flank dip to the northeast about 40 ft. in 1/2 mile, the strike of the fold being northwest and southeast. How far oil will be found down the gentle southwest dip is unknown but probably the productive part of the fold will not exceed 1 mile in width, and possibly less. No. 3 British Petroleums well is on the strike of the fold 1 mile southeast of the two oil wells. The sand that was productive in Nos. 2-and 4 wells was not present in this well or, if present, was very thin and unproductive. Two other sand horizons, however, were encountered. The upper of these

Jan 3, 1925

By Kathleen M. Kowalski

This research explores the emergence of leadership in a crisis situation. The study by the U.S. Bureau of Mines focuses on three underground mine fires and the resulting evacuations. The subjects for this study are 48 coal miners, who evacuated the mines as part of eight escape groups, The subjects described their escape during an open-ended interview. Data were coded according to: (a) evidence of leadership behavior, (b) evidence of lack of leadership behavior, and (c) characteristics of the individual in each group who led the subjects out of the mine. During analyses, attributes of the leaders, who facilitated the escapes, were noted and compared as were instances of lack of leadership. The structure of the group leadership before the crisis was compared with the reality of the leadership during the crisis. Some groups experienced an apparent breakdown of leadership during their escape, while others witnessed the emergence of leadership. Consensus characteristics of the leaders, who emerged during these crises, are discussed and generalizations drawn. Research into leadership during emergency escapes is needed to provide information for training in prevention, escape, and rescue. The authors suggest questions for further investigation and topics for further inquiry into the area of leadership evolvement during crisis.

Jan 1, 1994

By Alice V. Peter

The rare-earth group are among the least familiar of the 92 known elements. Moreover, the relatively few people who have even heard of the rare earths ordinarily regard them merely as very rare elements having unusual names but doubtful commercial application. This typical attitude can be attributed partly to the fact that no commercial uses have been developed for most of the members of the group and partly to the fact that those which do enter into useful articles do so anonymously. Most people speak with a degree of familiarity of the "chromium" plating on their automobiles or household appliances; "antimony" ash trays and cigarette boxes are on sale in many department stores; and "tungsten" lamps and even "molybdenum" steels are advertised in popular magazines. However, the average user of a pocket cigarette lighter is not conscious that the important sparking element is a "flint" made from ferrocerium, and if he does chap on to inquire about the composition he is likely to be told that it is "sparking alloy", "misch metal", or 'pyrophoric alloy." Similarly, the wearer of spectacles made of "Crookes" or other tinted glass probably is not aware that the light softening effects are due to the presence of rare-earth oxides, or that the arc light on his street may owe its brilliance to cerium fluoride in the carbon electrode. Despite a variety of practical applications, however, most of the rare-earth metals still must be listed as scientific curiosities. In fact, little is known as to the properties which may make them useful products at some future date. Meanwhile it is important to note that Nature has been relatively generous in her distribution of the rare earths and that adequate supplies of most of them will be forthcoming when these elements have proved their worth as commercial products.

Jan 1, 1935

By J. Koster

During the past several years, alunite from the Marysvale (Utah) region has been the subject of investigation by the Electrometallurgical Section of the Bureau of Mines. The nature and occurrence of this mineral, with considerable data on the Utah deposits, together with a number of results of preliminary experiments, have been given in a previous report.6/ The geology of the Marysvale region has been reviewed recently.7/ The present paper reports the results obtained by a method involving the sintering of alunite with boric acid and subsequent treatment of the sinter to produce alumina and potassium sulphate.

Jan 1, 1939

By W. M. Dressel

A simple field test for detecting the presence of germanium in rocks, coals, and flue dust has been developed by the Bureau of Mines. The method consists of dissolving germanium from the samples by either acid or fusion treatment methods, adding a few drops of hematein or phenylfluorone dye, and extracting the resulting colored complex with carbon tetrachloride. INTRODUCTION Germanium is obtained commercially as a byproduct of zinc production, as a coproduct of base-metal refining from germanium-bearing mineral, and as a recovered product from the ash of some coals. The growing use of germanium in the electronics industry has increased demand for this semiconducting metal to the extent that an intensive search for new sources of supply is necessary.

Jan 1, 1962

By Galen G. Waddell

The Deep Creek zinc and lead mine afforded an excellent example of a relatively small underground mine operation that approached the low mining costs of large, highly mechanized mines, An open stope mining method incorporating sublevel benches and vertical long holes was used (fig. 1). Detailed descriptions are given on the exploration program, stope development, stoping procedures, and pillar removal. Pressure grouting was used to check the inflow of water and thus prolong the life of the mine. Statistics on mining costs and on electric power consumption, haulage from mine to mill, and milling costs are included.

Jan 1, 1963

By Daniel J. Brunner

The U. S. Department of Energy (D.O.E.) requires that the prospective nuclear waste repository in Basalt at Hanford, Washington, comply with State of California mine and tunnel safety orders. These regulations require that all main fans be installed in such a manner as to permit prompt reversal of airflow. This paper evaluates the requirement of air reversal and the appropriateness of imposing such regulations on the proposed nuclear waste repository in Basalt.

Jan 1, 1988

By Elmer A. Jones

Like the caboose on the end of a long freight train L made up of mineral and metal processing and consuming industries, the mining industry progresses according to the movement of the train to which it is coupled. Sometimes the caboose rolls smoothly; occasionally it bumps along on the ties; almost always it is under criticism from someone for being too small, too large, too expensive, foolishly progressive, or hopelessly out of date. We who ride in the caboose are used to the rough by now, but it is nice now and then to have a bit of the smooth. Last year the train of industrial production rolled ahead swiftly and smoothly, and, except for a hot-box caused by strikes in copper mines, so did the caboose. As is brought out elsewhere in this issue, the outlook for 1956 is for more of the same.

Feb 1, 1956

By J. L. Gregg

A study of copper-base and silver-base alloys was made with the object of finding, if possible, useful alloys subject to dispersion hardening. These studies led to the discovery of several alloys showing considerable dispersion hardening, the most important of which, the alloys of copper with iron, nickel, cobalt and chromium silicides, have since been very ably reported by M. G. Corson.l This paper is offered as a few notes covering alloys other than those described by Corson and some further data on the silicide alloys. Copper Alloys For the purpose of making a rapid survey of copper alloys that might show useful dispersion-hardening phenomena, various alloys were prepared containing 3 per cent. of additional elements added in such proportion that possible compounds could be formed without an excess of either added element. These alloys in the form of rolled or forged pieces were quenched in water from a temperature of 871" C. (1800" F.) and subsequently aged at various lower temperatures for l-hr. periods. The comparison of the Rockwell hardness of the quenched alloys with the maximum hardness of the alloys after aging was used as a measure of the dispersion hardening. Table 1 shows the Rockwell "E" hardness 1/8-in. ball, 100-kg. load) of the quenched alloys, together with the maximum hardness resulting from aging. The reheating temperature given in this table is the aging temperature at which maximum hardness resulted from a l-hr. sojourn. From this table it may be observed that only the silicide alloys showed significant dispersion hardening. Of these, the only one not described by Corson is the Cu-Be-Si alloy. This alloy contained 1.35 per cent. beryllium and 1.78 per cent. silicon, which is approximately equivalent to 3 per cent. Be2Si. It had a yellow color and scaled much less than the other silicide alloys upon heating. It could be worked easily either hot or cold but hardened very rapidly on cold working. The annealed alloy upon drawing from a diameter

Jan 1, 1929

By Paul D. Tomlingson

World class performance is the ultimate objective of many maintenance organizations. It marks the organization as a leader in its industry and sets it apart as the ultimate achiever. But what is a “world class” standard and how can it be achieved? Is there a yardstick by which an industrial organization can measure the relative performance of its maintenance activity and compare it with performance levels that universally identify “world class” status? Are there financial formulas, achievements, evaluation techniques or indices that provide this yardstick?

Jan 1, 2006

By Ishwinder Grewal, Michael Fullam

Many factors affect the overall performance of a gravity circuit beyond that of the primary gravity recovery device. It is critical to examine the gravity circuit in its entirety in order to determine the dominant operating variables that affect overall performance. Knelson has developed a mathematical model which has been used to assist in the design of gravity circuits, and in particular, in making accurate predictions of plant scale gravity recovery. More recently, inclusion of recovery by particle size class and additional data from various mine sites and research studies has made the model more robust. The model is now able to predict GRG (gravity-recoverable-gold) recoveries using various devices such as centrifugal concentrators, shaking tables, jigs and flash-flotation within the grinding circuit. The benefits derived by these recent advancements in modeling capability are two-fold; the first is as a tool to assist in circuit design and correct equipment selection and the second is as an analytical tool to help to evaluate and enhance the performance of existing gravity circuits.

Jan 1, 2006

Very few data are available about production in this county. The amount mined was used locally, or shipped by river, until 1839 when the canal was completed to Dunnsburg. Only partial records for four years remain of canal shipments. Considerable coal was used locally by the iron works at Farrandsville for some years. Rail shipments started in 1861 and those shown are the estimated shipments of these mines as compared with the mines in other counties served by the Philadelphia and Erie Railroad, the total tonnages being given in the annual reports to the Auditor General. It is not likely that any coal used by the railroad is included in these figures. (Table 40.)

Jan 1, 1942

By T. A. Rickard

RICO, in the southwestern corner of Colorado, is one of the productive mining centers of the San Juan region, so-called because its waters drain into the river of that name, which is tributary to the Colorado. The San Juan region includes the counties of Ouray, Hinsdale, San Miguel, Dolores, San Juan and Montezuma. It is traversed by a network of picturesque mountain ranges on whose lofty summits there rests perpetual snow. The region is peculiarly rugged, and, in the early days of its development, tested to the full the hardihood of the adventurers who first explored its can ions 111 search for gold and silver. A prospecting party, guided by Jim Baker, scout and trapper, penetrated in 1861 this part of the territory of Kansas. At that time the country was in the possession of the Ute Indians. In October, 1873, by the Brunot treaty, they ceded to the United States Government the richest mineral-bearing portion of their

Jan 1, 1897

Flotation Research on Cassiterite of Tailings

Sep 13, 2010

Pillar design is the first line of defense against rock falls—the greatest single safety hazard faced by underground coal miners in the United States and abroad. To help advance the state of the art in this fundamental mining science, the National Institute for Occupational Safety and Health organized the Second International Workshop on Coal Pillar Mechanics and Design. The workshop was held in Vail, CO, on June 6,1999, in association with the 37th U.S. Rock Mechanics Symposium. The proceedings include 15 papers from leading ground control specialists in the United States, Canada, Australia, the United Kingdom, and the Republic of South Africa. The papers address the entire range of issues associated with coal pillars and have a decidedly practical flavor. Topics include numerical modeling, empirical design formulas based on case histories, field measurements, and post failure mechanics.

Jan 5, 1999

By Nancy Redhead

El buen funcionamiento de los equipos de una fábrica depende de la energía eléctrica. Si ocurriesen problemas con esta, se resuelven con tecnologías convencionales como la utilización de bancos de condensadores, filtros activos, UPS, estabilizadores de tensión y protectores de sobretensiones. Sin embargo, el riesgo de utilizarlas es que algunas veces son incompletas o no son compatibles. En ese sentido, el presente texto plantea una nueva tecnología utilizada en otros países que corrige los problemas eléctricos de forma completa y segura. Este un sistema automático completo de ahorro de energía y de la calidad de la onda eléctrica que está dotado de un microprocesador y analiza el voltaje, corriente, factor de potencia y armónicos. Asímismo, permite recuperar la energía perdida para luego filtrarla y devolverla a la red -al tiempo que se agrega una carga adicional sin necesidad de incrementar el tamaño de los transformadores o conductores.

Apr 1, 2013